Flexible pen



FIG. 1 is a front elevational view of a flexible pen showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof; and

FIG. 7 is a front elevational view of the flexible pen with the cap retracted to uncover the writing tip. 

The ornamental design for a flexible pen, as shown. 